Buggy, Aoife and McManus, Jennifer and Brodkorb, André and Hogan, Sean A. and Fenelon, Mark (2018) Pilot-scale formation of whey protein aggregates determine the stability of heat-treated whey protein solutions— Effect of pH and protein concentration. Journal of Dairy Science, 101 (12). pp. 10819-10830. ISSN 1525-3198

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Abstract

Denaturation and consequent aggregation in whey protein solutions is critical to product functionality during processing. Solutions of whey protein isolate (WPI) prepared at 1, 4, 8, and 12% (wt/wt) and pH 6.2, 6.7, or 7.2 were subjected to heat treatment (85°C × 30 s) using a pilot-scale heat exchanger. The effects of heat treatment on whey protein denaturation and aggregation were determined by chromatography, particle size, turbidity, and rheological analyses. The influence of pH and WPI concentration during heat treatment on the thermal stability of the resulting dispersions was also investigated. Whey protein isolate solutions heated at pH 6.2 were more extensively denatured, had a greater proportion of insoluble aggregates, higher particle size and turbidity, and were significantly less heat-stable than equivalent samples prepared at pH 6.7 and 7.2. The effects of WPI concentration on denaturation/aggregation behavior were more apparent at higher pH where the stabilizing effects of charge repulsion became increasingly influential. Solutions containing 12% (wt/ wt) WPI had significantly higher apparent viscosities, at each pH, compared with lower protein concentrations, with solutions prepared at pH 6.2 forming a gel. Smaller average particle size and a higher proportion of soluble aggregates in WPI solutions, pre-heated at pH 6.7 and 7.2, resulted in improved thermal stability on subsequent heating. Higher pH during secondary heating also increased thermal stability. This study offers insight into the interactive effects of pH and whey protein concentration during pilot-scale processing and demonstrates how protein functionality can be controlled through manipulation of these factors.

Item Type:	Article
Keywords:	whey protein; denaturation; aggregation; concentration;
Academic Unit:	Faculty of Science and Engineering > Chemistry
Item ID:	13064
Identification Number:	https://doi.org/10.3168/jds.2017-14177
Depositing User:	Jennifer McManus
Date Deposited:	18 Jun 2020 14:22
Journal or Publication Title:	Journal of Dairy Science
Publisher:	American Dairy Science Association
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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